The object of the method is to find properties such as the permeability, the porosity or the natural pressure, of the layers of materials in the subsoil. The knowledge of such properties is notably useful if exploitation of the subsoil is envisaged, for example to extract hydrocarbons therefrom.
Document FR-A-2 747 470 describes a method of testing seal-tightness of a subterranean fluid storage cavity. According to this method, the cavity and a well that gives access to it from the surface are filled with two non-miscible fluids, the interface between the two fluids being positioned at a desired depth. To simulate a leak at this depth, predetermined quantities of one of the two fluids are injected or subtracted. The pressures at the well head are measured, together with the position of the interface before and after each injection or removal. The leak flow rate is then estimated from these measurements.
Such a method makes it possible to qualify the seal-tightness of the cavity by estimating a leak flow rate at the casing shoe of the well. This method does not make it possible to estimate the position of the leak, or estimate physical parameters of the materials surrounding the well at a given depth. Furthermore, this method does not make it possible to obtain physical parameters of several layers of materials in the well.